I've always thought that it is because most people can only afford to have one system and people like to think that the choice they made is the correct one.
Until the most recent updates,XBox One and Playstation4, we have always purchased one of each, just spaced them out by a year at a time. This time only Playstation 4, and A New 3DS for each person. We always have Nintendo products-they are the only ones that I can play and I do the budget.